1 ## Copyright (C) 2012 Rik Wehbring
2 ## Copyright (C) 1995-2012 Kurt Hornik
4 ## This file is part of Octave.
6 ## Octave is free software; you can redistribute it and/or modify it
7 ## under the terms of the GNU General Public License as published by
8 ## the Free Software Foundation; either version 3 of the License, or (at
9 ## your option) any later version.
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13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 ## General Public License for more details.
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18 ## <http://www.gnu.org/licenses/>.
21 ## @deftypefn {Function File} {} fcdf (@var{x}, @var{m}, @var{n})
22 ## For each element of @var{x}, compute the cumulative distribution function
23 ## (CDF) at @var{x} of the F distribution with @var{m} and @var{n} degrees of
27 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
28 ## Description: CDF of the F distribution
30 function cdf = fcdf (x, m, n)
36 if (!isscalar (m) || !isscalar (n))
37 [retval, x, m, n] = common_size (x, m, n);
39 error ("fcdf: X, M, and N must be of common size or scalars");
43 if (iscomplex (x) || iscomplex (m) || iscomplex (n))
44 error ("fcdf: X, M, and N must not be complex");
47 if (isa (x, "single") || isa (m, "single") || isa (n, "single"))
48 cdf = zeros (size (x), "single");
50 cdf = zeros (size (x));
53 k = isnan (x) | !(m > 0) | !(m < Inf) | !(n > 0) | !(n < Inf);
56 k = (x == Inf) & (m > 0) & (m < Inf) & (n > 0) & (n < Inf);
59 k = (x > 0) & (x < Inf) & (m > 0) & (m < Inf) & (n > 0) & (n < Inf);
60 if (isscalar (m) && isscalar (n))
61 cdf(k) = 1 - betainc (1 ./ (1 + m * x(k) / n), n/2, m/2);
63 cdf(k) = 1 - betainc (1 ./ (1 + m(k) .* x(k) ./ n(k)), n(k)/2, m(k)/2);
70 %! x = [-1 0 0.5 1 2 Inf];
71 %! y = [0 0 1/3 1/2 2/3 1];
72 %!assert(fcdf (x, 2*ones(1,6), 2*ones(1,6)), y, eps);
73 %!assert(fcdf (x, 2, 2*ones(1,6)), y, eps);
74 %!assert(fcdf (x, 2*ones(1,6), 2), y, eps);
75 %!assert(fcdf (x, [0 NaN Inf 2 2 2], 2), [NaN NaN NaN y(4:6)], eps);
76 %!assert(fcdf (x, 2, [0 NaN Inf 2 2 2]), [NaN NaN NaN y(4:6)], eps);
77 %!assert(fcdf ([x(1:2) NaN x(4:6)], 2, 2), [y(1:2) NaN y(4:6)], eps);
79 %% Test class of input preserved
80 %!assert(fcdf ([x, NaN], 2, 2), [y, NaN], eps);
81 %!assert(fcdf (single([x, NaN]), 2, 2), single([y, NaN]), eps("single"));
82 %!assert(fcdf ([x, NaN], single(2), 2), single([y, NaN]), eps("single"));
83 %!assert(fcdf ([x, NaN], 2, single(2)), single([y, NaN]), eps("single"));
85 %% Test input validation
89 %!error fcdf (1,2,3,4)
90 %!error fcdf (ones(3),ones(2),ones(2))
91 %!error fcdf (ones(2),ones(3),ones(2))
92 %!error fcdf (ones(2),ones(2),ones(3))
93 %!error fcdf (i, 2, 2)
94 %!error fcdf (2, i, 2)
95 %!error fcdf (2, 2, i)